Arc resistant switch



March 16, 1965 B. J. GOLBECK 3,174,000

ARC RESISTANT SWITCH Filed Sept. 19, 1962 INVENTOR.

United States Patent 3,174,000 ARC RESISTANT SWITCH Bernard J. Golbecir,Crystal Lake, 111., assignor to Oak Manufacturing (10., a corporation ofDelaware Filed Sept. 19, 1962, Ser. No. 224,780 11 Claims. (Ci. 20tl-11)This invention relates to an electric switch, and more particularly to ahigh power capacity electric switch.

In high power capacity electric switches, arcing across switch contactspresents a major problem particularly during opening of the contacts andto some extent upon closing of the contacts. Various expedients havebeen suggested for overcoming such arcing problems, often by provisionof low resistance contact for carrying normal electrical loads when theswitch is closed and a high arc resistant contact for controlling arcingas the switch is being opened. However, such prior expedients havegenerally entailed complicated switch constructions, often of abasically impractical nature, or of such a nature as to substantiallyincrease the cost of the switch.

The primary object of this invention is to provide a new and usefulelectrical switch.

An important object is provision of a new and useful electric switch forcontrolling arcing during operation of the switch.

A more specific object is provision of a new and useful high powercapacity electric switch having a high are resistant contactelectrically connected with a high conductive contact, and mounted inoperative assembly in a simple and practical manner.

Other objects and advantages of the inveniton will become readilyapparent from the following detailed description taken in connectionwith the accompanying drawings, in which:

FIGURE 1 is a facial view of an embodiment of an electric switchincorporating features of the invention;

FIGURE 2 is an enlarged, fragmentary sectional view taken generallyalong the line 22 of FIGURE 1;

FIGURE 3 is a fragmentary sectional view taken generally along the line33 of FIGURE 2;

FIGURE 4 is a fragmentary sectional view taken generally along the line4-4 of FIGURE 2;

FIGURE 5 is a side view of another embodiment of an electric switchincorporating features of the invention; and

FIGURE 6 is a sectional view taken generally along the line 66 FIGURE 5.

While illustrative embodiments of the invention are shown in thedrawings and will be described in detail herein, the invention issusceptible of embodiment in many different forms, and it should beunderstood that the present disclosure is to be considered as anexemplification of the principles of the invention and is not in tendedto limit the invention to the embodiments illustrated. The scope of theinvention will be pointed out in the appended claims.

The invention is, in brief, directed to a practical solution to theproblem of contact arcing during operation of high power capacityelectric switches. This problem is solved by providing cooperatingcontacts in a switch including a high are resistant contact electricallyconnected with a high conductive contact in such a manner as to providea simple and durable commercially practical switch assembly.

With reference to FIGURES 1 through 4 of the drawings, a rotary electricswitch has a threaded hub 10 for mounting the switch in a suitablyapertured panel, or the like. A rotary switch operating shaft 11 isjournalled in hub 10 and mounts a switch rotor 12 received within acentral opening 13 of a switch stator 14. In the illustrated embodimenta ball detent-type indexing assembly 15 3,1743% Patented Mar. 16, 1965"ice includes a plate 16 fixedly secured to hub 10 in any suitablemanner as by a rolled connection 17, and plate 16 fixedly secured tostator 14 in any suitable manner as by diametrically opposed bolts 18which may be telescoped through sleeves (not shown) between plate 16 andstator 14. Indexing assembly 15 also includes a small plate 19telescoped on shaft 11 and held against axial movement along the shafttoward rotor 12 by staked shaft portions 20, thus holding shaft 11against movement through hub 10 in a direction to the right as viewed inFIGURE 2. A C-Wash 21 received in a circumferential groove in shaft 11prevents movement of the shaft in an opposite direction.

Stator 14 has a non-conductive body 25 of any suitable material, forexample, a ceramic, and this body has opposite parallel faces 26 and 27,with resilient jaw contacts 28a and 2817 on opposite faces 26 and 27,respectively, of the stator and connected by electrically conductivefasteners such as rivets 29 to define pairs of contacts. The resilientjaws of the pair of contacts 28a and 28b are positioned in a path forengagement with contacts 35 and 36 on opposite parallel faces 37 and 38,respectively, of a non-conductive body 39 of rotor 12. Contact 35 ispart of a contact ring 40 extending slightly outwardly from rotor bodyface 37 so that it may be received between resilient jaws of a statorcontact 41. Similarly, rotor contact 36 is part of a contact ring 42 onrotor face 38 and extends slightly outwardly from rotor body 39 and isreceived between resilient jaws of a stator contact 43. Rings 40 and 42are mounted on opposite faces of rotor body 39 and are electricallyconnected with each other by means of a rivet 44 extending through therings and rotor body. Stator contacts 41 and 43 are mounted on oppositefaces of stator body 25 and electrically connected with each other as byrivets 45, in a manner similar to the connection of pairs of contacts28.

With the exception of contacts 28b, and rotor ring 42 and including itscontact 36, all of the other contact structures previously described arepreferably of a high electrically conductive material thus providing alow contact resistance for carrying normal electrical loads, and asuitable material for this purpose is com silver. Contacts 28b and rotorring 42 are of a high arc resistant material such as silver-cadmiumalloy or silver-nickel alloy, and contact 36 is wider around acircumferential path of movement about the axis of shaft 11 than isrotor contact 35, so that as pairs of contacts 28a and 281) are engagedby the rotor contacts, rotor contact 36 engages its. cooperating contact28b of the pair before high conductance rotor contact 35 engages itsstator contact 2801. A circuit is completed from contact 43 throughcontact 36 to contact 28b of the pair of contacts before a circuit iscompleted from stator contact 41 through contact 35 to the other contact28a of the pair of contacts, preventing arcing between cooperatingnormal load carrying contacts 28a and 35 of high current conductivematerial, upon closing of cooperating contacts. Similarly, highconductance rotor contact 35 disengages its cooperating stator contact2dr: before high are resistant rotor contact 36 disengages its rotorcontact 28]), again preventing arcing which would damage the highconductive contacts. Contacts 28b and rotor ring 42 may be made of highconductive material, in which event they absorb arcing until the contact36 is burned to the same width as contact 35.

Referring to FIGURES 5 and 6, a slide-type switch is shown wherein anon-conductive base 50 carries a series of pairs of contacts 51a and 51bwhich are connected together. Contacts 51a and 51b may both be of highconductive material in order to facilitate economic manufacture of theswitch, or contacts 51a may preferably be of high arc resistantmaterial, and the same consideration applies to the foregoingembodiment. The contacts of a each pair are opposed to each other alongopposite edge portions of the base, and secured to the base in anysuitable manner. A slide 52 has a relatively short high conductivecontact 53 movable in a path for engaging contacts 51a along one edge ofbase 50, and a relatively long contact 54, longer than contact 53 andmounted for movement on slide 52 to engage the contacts 51b along theother edge of base 50. Contact 54 may be made of high conductivematerial but is preferably of high are resistant material for the samereasons as previously discussed. Contacts 53 and 54 are connected toeach other in a suitable manner as by connectors 55 and are mounted onthe slide as by tabs 56 so that high are resistant contact 54 engagesits cooperating contact 51b of the respective pair of contacts prior toengagement of high conductive conductive contact 53 with its cooperatingcontact 51a of the respective pair. As previously described, high areresistant contact 54 disengages its cooperating contact 51b of therespective pair of contacts after high conductive contact 53 hasdisengaged its cooperating contact 51a of the respective pair ofcontacts.

I claim:

1. In an electric switch for controlling arcing during operation of theswitch: a non-conductive base; a plurality of pairs of contacts disposedin a path; electrical conductive means, one connected with the contactsof each pair of contacts; means mounting the pairs of contacts on saidbase; a non-conductive member movable along said path, with a highconductive contact and a high are resistant contact mounted on saidmember, said high arc resistant contact being longer along said paththan said high conductive contact, and electrical conductive meansconnected with the member contacts whereby the member contactsselectively engage said pairs of contacts upon movement of said memberalong said path with said high conductive contact engaging one contactof the selected pair of contacts and said high are resistant contactengaging the other contact of the selected pair prior to said engagementof said high conductive contact, and with said high are resistantcontact disengaging said other contact after disengagement of said highconductive contact from said one contact of the selected pair; and meansmounting said member for movement along said path and said membercontacts in said path.

2. In an electric switch for controlling arcing during operation of theswitch: a base; a pair of contacts mounted on said base and electricallyconnected with each other, one of said contacts being a high conductivecontact and the other contact being a high are resistant contact; amember movable in a given path with respect to said base and inconsistent spaced relationship with respect to said base; a highconductive contact and a high are resistant contact on said membermovable into and out of engagement with said high conductive basecontact and said high are resistant base contact, respectively, saidhigh are resistant member contact having a greater span of engagementwith its base contact than said high conductive member contact has withits base contact; and means mounting the member contacts for releasableengagement with their respective base contacts upon movement of saidmember along said path with said high are resistant contact engaging itsbase contact prior to engagement of said high conductive contact withits base contact, and with said high are resistant contact disengagingits base contact after disengagement of said high conductive contactfrom its base contact; and means mounting said member for movement ofsaid member contacts in said path.

3. In an electric switch for controlling arcing during operation of theswitch: a base; a pair of contacts mounted on said base and electricallyconnected with each other; a member movable in a given path with respectto said base and in consistent spaced relationship with respect to saidbase; contacts on said member, one movable into and out of engagementwith each of said base contacts, a first of said member contacts havinga greater span of engagement with its base contact than the other membercontact has with its base contact; and means mounting the membercontacts for releasable engagement with their respective base contactsupon movement of said member along said path with said first membercontact engaging its base contact prior to engagement of said othermember contact with its base contact, and with said first member contactdisengaging its base contact after disengagement of said other membercontact from its base contact; and means mounting said member formovement of said member contacts in said path.

4. In a slide-type electric switch for controlling arcing duringoperation of the switch: a non-conductive base having a face; aplurality of pairs of contacts mounted on said face in a predeterminedpath, each contact being electrically connected with the other contactof its pair; a non-conductive slide member movable along said path inconsistent spaced relationship with respect to said base and having aface opposed to the base face; a high conductive contact and a high areresistant contact electrially connected to each other, said high areresistant contact being wider along said path than said high conductivecontact, and means mounting the last said contacts on the slide face forselective engagement with said pairs of contacts upon movement of saidslide along said path with said high conductive contact connecting firstcontacts of each of two. selected pairs of contacts and said high areresistant contact connecting second contacts of each of the last saidtwo selected pairs of contacts prior to said high conductive contactengaging both said first contacts, and with said high are resistantcontact disengaging one of said second contacts after disengagement ofsaid high conductive contact from one of said contacts of the selectedpair; and means mounting said slide for sliding movement with respect tosaid base with said slide face opposed to said base face and said slidecontacts in said path.

5. In a slide-type electric switch for controlling arcing duringoperation of the switch: a base; a plurality of pairs of contactsmounted on said base to define a predetermined path, each contact beingelectrically connected with the other contact of its pair; a slidemovable along said path and opposed to the base; a high conductivecontact and a hi h are resistant contact electrically connected to eachother, said high are resistant contact being wider along said path thansaid high conductive contact; and means mounting the last said contactson said slide body for selective engagement with said pairs of contactsupon movement of said slide along said path with said high conductivecontact engaging a first contact of the selected pair of contacts andsaid high are resistant contact engaging a second contact of theselected pair of contacts prior to said high conductive contact engagingsaid first contact, and said high arc resistant contact disengaging saidsecond contact after disengagement of said high conductive contact fromsaid first contact of the selected pair; and means mounting said slidefor sliding movement with respect to said base and with said slidecontacts in said path.

6. In a slide-type electric switch for controlling arcing duringoperation of the switch: a base; a pair of elec trically interconnectedcontacts mounted on said base and disposed in a predetermined path; aslide movable along said path and opposed to the base; a high conductivecon tact and a high are resistant contact electrically connected to eachother and one movable into and out of engagement with each of the basecontacts, said high are resistant con tact having a greater span ofengagement with its base contact than said high conductive contact haswith its base contact; and means mounting the high are resistant andhigh conductive contacts on said slide for selective engagement withsaid base contacts upon movement of said slide along said path with saidhigh are resistant contact engaging its base contact prior to engagementof said high conductive contact with its base contact and said high areresistant contact disengaging its base contact after disengagement ofsaid high conductive contact from its base contact; and means mountingsaid slide for sliding movement with respect to said base with saidslide contacts in said path.

7. In a slide-type electric switch for controlling arcing duringoperation of the switch: a base; a pair of electrically interconnectedcontacts mounted on said base and disposed in a predetermined path; aslide movable along said path and opposed to the base; a pair ofcontacts electrically connected to each other and one movable into andout of engagement with each of the base contacts, a first of said pairof contacts having a greater span of engagement With its base contactthan the other of said pair of contacts has with its base contact; andmeans mounting said pair of contacts on said slide (for selectiveengagement with said base contacts upon movement of said slide alongsaid path with said first contact engaging its base contact prior toengagement of said other contact with its base contact and said firstcontact disengaging its base contact after disengagement of said othercontact from its base contact; and means mounting said slide for slidingmovement with respect to said base with said slide contacts in saidpath.

8. In a rotary-type electric switch for controlling arcing duringoperation of the switch: a stator base having a nonconductive body withopposite faces; a plurality of pairs of contacts radially disposed aboutan axis, the contacts of each pair being opposed to each other, one oneach of said stator faces; electrical conductive fastening meansextending through said stator body, one connected with the contacts ofeach pair of contacts and mounting the respective pair of contacts onsaid body; a rotor member movable in a predetermined path and inconsistent spaced relationship with respect to said stator, said rotorhaving a non-conductive body with opposite faces; a high conduo tivecontact on one of said rotor faces and a high are resistant contact onthe opposite rotor face and opposed to said high conductive contact,said high are resistant contact being wider along said path than saidhigh conductive contact; electrical conductive fastening means extendingthrough said rotor body and connected with the rotor contacts andmounting the rotor contacts on said rotor body for selective engagementwith said pairs of contacts upon movement of said rotor along saidpredetermined path with said high conductive contact engaging onecontact of the selected pair of contacts and said high are resistantcontact engaging the other contact of the selected pair prior to saidengagement of said high conductive contact, and with said high arcresistant contact disengaging said other contact after disengagement ofsaid high conductive contact from said one contact of the selected pair;and means mounting said rotor for rotation about said axis and saidrotor contacts in said path.

9. In a rotary-type electric switch for controlling arcing duringoperation of the switch: a stator having a body with opposite faces,pairs of contacts disposed about an axis, one contact of each pair oneach of said stator faces; means electrically connecting the contacts ofeach pair; a rotor movable in a predetermined path with respect to saidstator, said rotor having a body with opposite faces, a high conductivecontact on one of said rotor faces and a high are resistant contact onthe opposite rotor face, said high are resistant contact being Wideralong said path than said high conductive contact, means electricallyconnecting the rotor contacts; means mounting the rotor contacts on saidrotor body for selective engagement with said pairs of contacts uponmovement of said rotor along said predetermined path with said highconductive contact engaging one contact of the selected pair of contactsand said high are resistant contact engaging the other contact of theselected pair prior to said engagement of said high conductive contact,and with said high are resistant contact disengaging said other contactafter disengagement of said high conductive contact from said onecontact of the selected pair; and means mounting said rotor for rotationabout said axis and said rotor contacts in said path.

10. In a rotary-type electric switch for controlling arcing duringoperation of the switch: a stator having a body; a pair of contactsmounted on said body and electrically connected with each other; a rotorhaving a body movable in a predetermined path with respect to saidstator; a high conductive contact and a high are resistant contact onsaid rotor body and one movable into and out of engagement with each ofsaid stator contacts, said high are resistant contact having a greaterspan of engagement with its stator contact than said high conductivecontact has with its stator contact; means mounting the rotor contactson said rotor body for releasable engagement with said stator contactsupon movement of said rotor along said predetermined path with said highare resistant contact engaging its stator contact prior to engagement ofsaid high conductive contact with its stator contact, and with said higharc resistant contact disengaging its stator contact after disengagementof said high conductive contact from its stator contact; and meansmounting said rotor for rotation of said rotor contacts in said path.

11. In a rotary-type electric switch for controlling arcing duringoperation of the switch: a stator having a body; a pair of contactsmounted on said body and electrically connected with each other; a rotorhaving a body movable in a predetermined path with respect to saidstator; a pair of contacts on said rotor body and one movable into andout of engagement with each of said stator contacts, a first of saidrotor contacts having a greater span of engagement with its statorcontact than the other of said rotor contacts has with its statorcontact; means mounting the rotor contacts on said rotor body forreleasable engagement with said stator contacts upon movement of saidrotor along said predetermined path with said first rotor contactengaging its stator contact prior to engagement of said other rotorcontact with its stator contact, and with said first rotor contactdisengaging its stator contact after disengagement of said first rotorcontact from its stator contact; and means mounting said rotor forrotation of said rotor contacts in said path.

References Cited by the Examiner UNITED STATES PATENTS 2,168,373 8/39Thompson 200-15 2,196,433 4/40 Allison 200-16 2,528,035 10/50 Clayton200-16 2,554,724 5/51 Williams 200-11 2,594,190 4/52 Mastney 200-112,671,137 3/54 Zaug 200-16 2,902,550 9/59 Allison 200-16 2,905,773 9/59Guillemant 200-16 2,949,511 8/60 Glueckstein et a1 200-11 BERNARD A.GILHEANY, Primary Examiner.

1. IN AN ELECTRIC SWITCH FOR CONTROLLING ARCING DURING OPERATION OF THESWITCH: A NON-CONDCTIVE BASE; A PLURALITY OF PAIRS OF CONTACTS DISPOSEDIN A PATH; ELECTRICAL CONDUCTIVE MEANS, ONE CONNECTED WITH THE CONTACTSOF EACH PAIR OF CONTACTS; MEANS MOUNTING THE PAIRS OF CONTACTS ON SAIDBASE; A NON-CONDUCTIVE MEMBER MOVABLE ALONG SAID PATH, WITH A HIGHCONDUCTIVE CONTACT AND A HIGH ARC RESISTANT CONTACT MOUNTED ON SAIDMEMBER, SAID HIGH ARC RESISTANT CONTACT BEING LONGER SAID PATH THAN SAIDHIGH CONDUCTIVE CONTACT, AND ELECTRICAL CONDUCTIVE MEANS CONNECTED WITHTHE MEMBER CONTACTS WHEREBY THE MEMBER CONTACTS SELECTIVELY ENGAGE SAIDPAIRS OF CONTACTS UPON MOVEMENT OF SAID MEMBER ALONG SAID PATH WITH SAIDHIGH CONDUCTIVE CONTACT ENGAGING ONE CONTACT OF THE